luca@gw:~$ echo | gcc -E -dD -
# 1 "<stdin>"
# 1 "<built-in>"
#define __STDC__ 1
#define __STDC_HOSTED__ 1
#define __GNUC__ 4
#define __GNUC_MINOR__ 4
#define __GNUC_PATCHLEVEL__ 5
#define __SIZE_TYPE__ unsigned int
#define __PTRDIFF_TYPE__ int
#define __WCHAR_TYPE__ unsigned int
#define __WINT_TYPE__ unsigned int
#define __INTMAX_TYPE__ long long int
#define __UINTMAX_TYPE__ long long unsigned int
#define __CHAR16_TYPE__ short unsigned int
#define __CHAR32_TYPE__ unsigned int
#define __GXX_ABI_VERSION 1002
#define __SCHAR_MAX__ 127
#define __SHRT_MAX__ 32767
#define __INT_MAX__ 2147483647
#define __LONG_MAX__ 2147483647L
#define __LONG_LONG_MAX__ 9223372036854775807LL
#define __WCHAR_MAX__ 4294967295U
#define __CHAR_BIT__ 8
#define __INTMAX_MAX__ 9223372036854775807LL
#define __FLT_EVAL_METHOD__ 0
#define __DEC_EVAL_METHOD__ 2
#define __FLT_RADIX__ 2
#define __FLT_MANT_DIG__ 24
#define __FLT_DIG__ 6
#define __FLT_MIN_EXP__ (-125)
#define __FLT_MIN_10_EXP__ (-37)
#define __FLT_MAX_EXP__ 128
#define __FLT_MAX_10_EXP__ 38
#define __FLT_MAX__ 3.40282347e+38F
#define __FLT_MIN__ 1.17549435e-38F
#define __FLT_EPSILON__ 1.19209290e-7F
#define __FLT_DENORM_MIN__ 1.40129846e-45F
#define __FLT_HAS_DENORM__ 1
#define __FLT_HAS_INFINITY__ 1
#define __FLT_HAS_QUIET_NAN__ 1
#define __DBL_MANT_DIG__ 53
#define __DBL_DIG__ 15
#define __DBL_MIN_EXP__ (-1021)
#define __DBL_MIN_10_EXP__ (-307)
#define __DBL_MAX_EXP__ 1024
#define __DBL_MAX_10_EXP__ 308
#define __DBL_MAX__ 1.7976931348623157e+308
#define __DBL_MIN__ 2.2250738585072014e-308
#define __DBL_EPSILON__ 2.2204460492503131e-16
#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
#define __DBL_HAS_DENORM__ 1
#define __DBL_HAS_INFINITY__ 1
#define __DBL_HAS_QUIET_NAN__ 1
#define __LDBL_MANT_DIG__ 53
#define __LDBL_DIG__ 15
#define __LDBL_MIN_EXP__ (-1021)
#define __LDBL_MIN_10_EXP__ (-307)
#define __LDBL_MAX_EXP__ 1024
#define __LDBL_MAX_10_EXP__ 308
#define __DECIMAL_DIG__ 17
#define __LDBL_MAX__ 1.7976931348623157e+308L
#define __LDBL_MIN__ 2.2250738585072014e-308L
#define __LDBL_EPSILON__ 2.2204460492503131e-16L
#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
#define __LDBL_HAS_DENORM__ 1
#define __LDBL_HAS_INFINITY__ 1
#define __LDBL_HAS_QUIET_NAN__ 1
#define __DEC32_MANT_DIG__ 7
#define __DEC32_MIN_EXP__ (-94)
#define __DEC32_MAX_EXP__ 97
#define __DEC32_MIN__ 1E-95DF
#define __DEC32_MAX__ 9.999999E96DF
#define __DEC32_EPSILON__ 1E-6DF
#define __DEC32_SUBNORMAL_MIN__ 0.000001E-95DF
#define __DEC64_MANT_DIG__ 16
#define __DEC64_MIN_EXP__ (-382)
#define __DEC64_MAX_EXP__ 385
#define __DEC64_MIN__ 1E-383DD
#define __DEC64_MAX__ 9.999999999999999E384DD
#define __DEC64_EPSILON__ 1E-15DD
#define __DEC64_SUBNORMAL_MIN__ 0.000000000000001E-383DD
#define __DEC128_MANT_DIG__ 34
#define __DEC128_MIN_EXP__ (-6142)
#define __DEC128_MAX_EXP__ 6145
#define __DEC128_MIN__ 1E-6143DL
#define __DEC128_MAX__ 9.999999999999999999999999999999999E6144DL
#define __DEC128_EPSILON__ 1E-33DL
#define __DEC128_SUBNORMAL_MIN__ 0.000000000000000000000000000000001E-6143DL
#define __REGISTER_PREFIX__ 
#define __USER_LABEL_PREFIX__ 
#define __VERSION__ "4.4.5"
#define __GNUC_GNU_INLINE__ 1
#define __NO_INLINE__ 1
#define __FINITE_MATH_ONLY__ 0
#define __CHAR_UNSIGNED__ 1
#define __SIZEOF_INT__ 4
#define __SIZEOF_LONG__ 4
#define __SIZEOF_LONG_LONG__ 8
#define __SIZEOF_SHORT__ 2
#define __SIZEOF_FLOAT__ 4
#define __SIZEOF_DOUBLE__ 8
#define __SIZEOF_LONG_DOUBLE__ 8
#define __SIZEOF_SIZE_T__ 4
#define __SIZEOF_WCHAR_T__ 4
#define __SIZEOF_WINT_T__ 4
#define __SIZEOF_PTRDIFF_T__ 4
#define __SIZEOF_POINTER__ 4
#define __arm__ 1
#define __APCS_32__ 1
#define __ARMEL__ 1
#define __SOFTFP__ 1
#define __VFP_FP__ 1
#define __THUMB_INTERWORK__ 1
#define __ARM_ARCH_4T__ 1
#define __ARM_EABI__ 1
#define __GXX_TYPEINFO_EQUALITY_INLINE 0
#define __gnu_linux__ 1
#define __linux 1
#define __linux__ 1
#define linux 1
#define __unix 1
#define __unix__ 1
#define unix 1
#define __ELF__ 1
#define __BIGGEST_ALIGNMENT__ 8
# 1 "<command-line>"
# 1 "<stdin>"
luca@gw:~$